Toner compositions

ABSTRACT

Toner particles are provided which may include a core and a shell, one or both of which may include a polyester gel. The gel in the shell and/or core may prevent a crystalline resin in the core from migrating to the toner surface.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is related to co-pending U.S. application Ser. Nos.12/198,981 and 12/198,999, both filed on Aug. 27, 2008, the entiredisclosures of each of which are hereby incorporated by reference intheir entirety.

BACKGROUND

The present disclosure relates to toners suitable forelectrophotographic apparatuses.

Numerous processes are within the purview of those skilled in the artfor the preparation of toners. Emulsion aggregation (EA) is one suchmethod. These toners may be formed by aggregating a colorant with alatex polymer formed by emulsion polymerization. For example, U.S. Pat.No. 5,853,943, the disclosure of which is hereby incorporated byreference in its entirety, is directed to a semi-continuous emulsionpolymerization process for preparing a latex by first forming a seedpolymer. Other examples of emulsion/aggregation/coalescing processes forthe preparation of toners are illustrated in U.S. Pat. Nos. 5,403,693,5,418,108, 5,364,729, and 5,346,797, the disclosures of each of whichare hereby incorporated by reference in their entirety. Other processesare disclosed in U.S. Pat. Nos. 5,527,658, 5,585,215, 5,650,255,5,650,256 and 5,501,935, the disclosures of each of which are herebyincorporated by reference in their entirety.

Polyester EA ultra low melt (ULM) toners have been prepared utilizingamorphous and crystalline polyester resins. While these toners mayexhibit excellent fusing properties including crease minimum fixingtemperature (NWT) and fusing latitude, peak gloss of these toners may beunacceptably high. Improved toners thus remain desirable.

SUMMARY

The present disclosure provides compositions suitable for use in formingtoners and methods for their production. In embodiments, a toner of thepresent disclosure may include a core including at least one amorphousresin, at least one crystalline resin, and one or more optionalingredients such as optional colorants, optional waxes, and combinationsthereof, and a shell including at least one amorphous resin such aspoly(propoxylated bisphenol co-fumarate), poly(ethoxylated bisphenolco-fumarate), poly(butyloxylated bisphenol co-fumarate),poly(co-propoxylated bisphenol co-ethoxylated bisphenol co-fumarate),poly(1,2-propylene fumarate), poly(propoxylated bisphenol co-maleate),poly(ethoxylated bisphenol co-maleate), poly(butyloxylated bisphenolco-maleate), poly(co-propoxylated bisphenol co-ethoxylated bisphenolco-maleate), poly(1,2-propylene maleate), poly(propoxylated bisphenolco-itaconate), poly(ethoxylated bisphenol co-itaconate),poly(butyloxylated bisphenol co-itaconate), poly(co-propoxylatedbisphenol co-ethoxylated bisphenol co-itaconate), poly(1,2-propyleneitaconate), and combinations thereof, wherein the amorphous resin in thecore, the amorphous resin in the shell, or both, includes a polyestergel.

In other embodiments, a toner of the present disclosure may include acore including at least one amorphous resin, at least one crystallineresin, and one or more optional ingredients such as optional colorants,optional waxes, and combinations thereof; and a shell including apolyester gel including at least one amorphous resin such aspoly(propoxylated bisphenol co-fumarate), poly(ethoxylated bisphenolco-fumarate), poly(butyloxylated bisphenol co-fumarate),poly(co-propoxylated bisphenol co-ethoxylated bisphenol co-fumarate),poly(1,2-propylene fumarate), poly(propoxylated bisphenol co-maleate),poly(ethoxylated bisphenol co-maleate), poly(butyloxylated bisphenolco-maleate), poly(co-propoxylated bisphenol co-ethoxylated bisphenolco-maleate), poly(1,2-propylene maleate), poly(propoxylated bisphenolco-itaconate), poly(ethoxylated bisphenol co-itaconate),poly(butyloxylated bisphenol co-itaconate), poly(co-propoxylatedbisphenol co-ethoxylated bisphenol co-itaconate), poly(1,2-propyleneitaconate), and combinations thereof, wherein from about 1% by weightabout 50% by weight of the polyester gel is crosslinked.

In embodiments, a process of the present disclosure may includecontacting at least one amorphous resin with at least one crystallineresin in a dispersion including at least one surfactant; contacting thedispersion with an optional colorant, at least one surfactant, and anoptional wax to form small particles; aggregating the small particles;contacting the small particles with a polyester gel latex including atleast one amorphous resin such as poly(propoxylated bisphenolco-fumarate), poly(ethoxylated bisphenol co-fumarate),poly(butyloxylated bisphenol co-fumarate), poly(co-propoxylatedbisphenol co-ethoxylated bisphenol co-fumarate), poly(1,2-propylenefumarate), poly(propoxylated bisphenol co-maleate), poly(ethoxylatedbisphenol co-maleate), poly(butyloxylated bisphenol co-maleate),poly(co-propoxylated bisphenol co-ethoxylated bisphenol co-maleate),poly(1,2-propylene maleate), poly(propoxylated bisphenol co-itaconate),poly(ethoxylated bisphenol co-itaconate), poly(butyloxylated bisphenolco-itaconate), poly(co-propoxylated bisphenol co-ethoxylated bisphenolco-itaconate), poly(1,2-propylene itaconate), and combinations thereof,to form a shell over the small particles; coalescing the small particlespossessing the shell to form toner particles; and recovering the tonerparticles.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the present disclosure will be described hereinbelow with reference to the figure wherein:

FIG. 1 is a graph comparing the viscosity of a toner of the presentdisclosure, possessing a polyester gel in the shell, with a controltoner; and

FIG. 2 is a graph comparing the charging (in both A-zone and C-zone) ofa toner of the present disclosure, possessing a polyester gel in theshell, with a control toner.

DETAILED DESCRIPTION

The present disclosure provides toner particles having desirablecharging and gloss properties. The toner particles possess a core-shellconfiguration, with a polyester gel or partially crosslinked polyesterin the core, the shell, or both. The gloss of the resulting toner may bereduced by the presence of the cross-linked polyester in the core and/orshell.

Core Resins

Any latex resin may be utilized in forming a toner core of the presentdisclosure. Such resins, in turn, may be made of any suitable monomer.In the event that the core resin is to be crosslinked, any crosslinkablelatex resin may be utilized. Suitable monomers useful in forming theresin include, but are not limited to, styrenes, acrylates,methacrylates, butadienes, isoprenes, acrylic acids, methacrylic acids,acrylonitriles, diol, diacid, diamine, diester, mixtures thereof, andthe like. Any monomer employed may be selected depending upon theparticular polymer to be utilized.

In embodiments, the polymer utilized to form the resin core may be apolyester resin, including the resins described in U.S. Pat. Nos.6,593,049 and 6,756,176, the disclosures of each of which are herebyincorporated by reference in their entirety. Suitable resins may alsoinclude a mixture of an amorphous polyester resin and a crystallinepolyester resin as described in U.S. Pat. No. 6,830,860, the disclosureof which is hereby incorporated by reference in its entirety.

In embodiments, the resin may be a polyester resin formed by reacting adiol with a diacid in the presence of an optional catalyst. For forminga crystalline polyester, suitable organic diols include aliphatic diolswith from about 2 to about 36 carbon atoms, such as 1,2-ethanediol,1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol,1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol,1,12-dodecanediol and the like; alkali sulfo-aliphatic diols such assodio 2-sulfo-1,2-ethanediol, lithio 2-sulfo-1,2-ethanediol, potassio2-sulfo-1,2-ethanediol, sodio 2-sulfo-1,3-propanediol, lithio2-sulfo-1,3-propanediol, potassio 2-sulfo-1,3-propanediol, mixturethereof, and the like. The aliphatic diol may be, for example, selectedin an amount of from about 40 to about 60 mole percent, in embodimentsfrom about 42 to about 55 mole percent, in embodiments from about 45 toabout 53 mole percent, and the alkali sulfo-aliphatic diol can beselected in an amount of from about 0 to about 10 mole percent, inembodiments from about 1 to about 4 mole percent of the resin.

Examples of organic diacids or diesters including vinyl diacids or vinyldiesters selected for the preparation of the crystalline resins includeoxalic acid, succinic acid, glutaric acid, adipic acid, suberic acid,azelaic acid, sebacic acid, fumaric acid, dimethyl fumarate, dimethylitaconate, cis, 1,4-diacetoxy-2-butene, diethyl fumarate, diethylmaleate, phthalic acid, isophthalic acid, terephthalic acid,naphthalene-2,6-dicarboxylic acid, naphthalene-2,7-dicarboxylic acid,cyclohexane dicarboxylic acid, malonic acid and mesaconic acid, adiester or anhydride thereof; and an alkali sulfo-organic diacid such asthe sodio, lithio or potassio salt of dimethyl-5-sulfo-isophthalate,dialkyl-5-sulfo-isophthalate-4-sulfo-1,8-naphthalic anhydride,4-sulfo-phthalic acid, dimethyl-4-sulfo-phthalate,dialkyl-4-sulfo-phthalate, 4-sulfophenyl-3,5-dicarbomethoxybenzene,6-sulfo-2-naphthyl-3,5-dicarbomethoxybenzene, sulfo-terephthalic acid,dimethyl-sulfo-terephthalate, 5-sulfo-isophthalic acid,dialkyl-sulfo-terephthalate, sulfoethanediol, 2-sulfopropanediol,2-sulfobutanediol, 3-sulfopentanediol, 2-sulfohexanediol,3-sulfo-2-methylpentanediol, 2-sulfo-3,3-dimethylpentanediol,sulfo-p-hydroxybenzoic acid, N,N-bis(2-hydroxyethyl)-2-amino ethanesulfonate, or mixtures thereof. The organic diacid may be selected in anamount of, for example, in embodiments from about 40 to about 60 molepercent, in embodiments from about 42 to about 52 mole percent, inembodiments from about 45 to about 50 mole percent, and the alkalisulfo-aliphatic diacid can be selected in an amount of from about 1 toabout 10 mole percent of the resin.

Examples of crystalline resins include polyesters, polyamides,polyimides, polyolefins, polyethylene, polybutylene, polyisobutyrate,ethylene-propylene copolymers, ethylene-vinyl acetate copolymers,polypropylene, mixtures thereof, and the like. Specific crystallineresins may be polyester based, such as poly(ethylene-adipate),poly(propylene-adipate), poly(butylene-adipate),poly(pentylene-adipate), poly(hexylene-adipate), poly(octylene-adipate),poly(ethylene-succinate), poly(propylene-succinate),poly(butylene-succinate), poly(pentylene-succinate),poly(hexylene-succinate), poly(octylene-succinate),poly(ethylene-sebacate), poly(propylene-sebacate),poly(butylene-sebacate), poly(pentylene-sebacate),poly(hexylene-sebacate), poly(octylene-sebacate), alkalicopoly(5-sulfoisophthaloyl)-copoly(ethylene-adipate), alkalicopoly(5-sulfoisophthaloyl)-copoly(propylene-adipate), alkalicopoly(5-sulfoisophthaloyl)-copoly(butylene-adipate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(pentylene-adipate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(hexylene-adipate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(octylene-adipate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(ethylene-adipate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(propylene-adipate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(butylene-adipate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(pentylene-adipate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(hexylene-adipate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(octylene-adipate), alkalicopoly(5-sulfoisophthaloyl)-copoly(ethylene-succinate), alkalicopoly(5-sulfoisophthaloyl)-copoly(propylene-succinate), alkalicopoly(5-sulfoisophthaloyl)-copoly(butylenes-succinate), alkalicopoly(5-sulfoisophthaloyl)-copoly(pentylene-succinate), alkalicopoly(5-sulfoisophthaloyl)-copoly(hexylene-succinate), alkalicopoly(5-sulfoisophthaloyl)-copoly(octylene-succinate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(ethylene-sebacate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(propylene-sebacate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(butylene-sebacate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(pentylene-sebacate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(hexylene-sebacate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(octylene-sebacate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(ethylene-adipate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(propylene-adipate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(butylene-adipate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(pentylene-adipate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(hexylene-adipate),poly(octylene-adipate), wherein alkali is a metal like sodium, lithiumor potassium. Examples of polyamides include poly(ethylene-adipamide),poly(propylene-adipamide), poly(butylenes-adipamide),poly(pentylene-adipamide), poly(hexylene-adipamide),poly(octylene-adipamide), poly(ethylene-succinamide), andpoly(propylene-sebecamide). Examples of polyimides includepoly(ethylene-adipimide), poly(propylene-adipimide),poly(butylene-adipimide), poly(pentylene-adipimide),poly(hexylene-adipimide), poly(octylene-adipimide),poly(ethylene-succinimide), poly(propylene-succinimide), andpoly(butylene-succinimide).

The crystalline resin may be present, for example, in an amount of fromabout 5 to about 50 percent by weight of the toner components, inembodiments from about 5 to about 35 percent by weight of the tonercomponents. The crystalline resin can possess various melting points of,for example, from about 30° C. to about 120° C., in embodiments fromabout 50° C. to about 90° C. The crystalline resin may have a numberaverage molecular weight (M_(n)), as measured by gel permeationchromatography (GPC) of, for example, from about 1,000 to about 50,000,in embodiments from about 2,000 to about 25,000, and a weight averagemolecular weight (M_(w)) of, for example, from about 2,000 to about100,000, in embodiments from about 3,000 to about 80,000, as determinedby Gel Permeation Chromatography using polystyrene standards. Themolecular weight distribution (M_(w)/M_(n)) of the crystalline resin maybe, for example, from about 2 to about 6, in embodiments from about 2 toabout 4.

Examples of diacid or diesters including vinyl diacids or vinyl diestersselected for the preparation of amorphous polyesters includedicarboxylic acids or diesters such as terephthalic acid, phthalic acid,isophthalic acid, fumaric acid, dimethyl fumarate, dimethyl itaconate,cis,1,4-diacetoxy-2-butene, diethyl fumarate, diethyl maleate, maleicacid, succinic acid, itaconic acid, succinic acid, succinic anhydride,dodecylsuccinic acid, dodecylsuccinic anhydride, glutaric acid, glutaricanhydride, adipic acid, pimelic acid, suberic acid, azelaic acid,dodecanediacid, dimethyl terephthalate, diethyl terephthalate,dimethylisophthalate, diethylisophthalate, dimethylphthalate, phthalicanhydride, diethylphthalate, dimethylsuccinate, dimethylfumarate,dimethylmaleate, dimethylglutarate, dimethyladipate, dimethyldodecylsuccinate, and combinations thereof. The organic diacid ordiester may be present, for example, in an amount from about 40 to about60 mole percent of the resin, in embodiments from about 42 to about 52mole percent of the resin, in embodiments from about 45 to about 50 molepercent of the resin.

Examples of diols utilized in generating the amorphous polyester include1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol,1,4-butanediol, pentanediol, hexanediol, 2,2-dimethylpropanediol,2,2,3-trimethylhexanediol, heptanediol, dodecanediol,bis(hydroxyethyl)-bisphenol A, bis(2-hydroxypropyl)-bisphenol A,1,4-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, xylenedimethanol,cyclohexanediol, diethylene glycol, bis(2-hydroxyethyl) oxide,dipropylene glycol, dibutylene, and combinations thereof. The amount oforganic diol selected can vary, and may be present, for example, in anamount from about 40 to about 60 mole percent of the resin, inembodiments from about 42 to about 55 mole percent of the resin, inembodiments from about 45 to about 53 mole percent of the resin.

Polycondensation catalysts which may be utilized for either thecrystalline or amorphous polyesters include tetraalkyl titanates,dialkyltin oxides such as dibutyltin oxide, tetraalkyltins such asdibutyltin dilaurate, and dialkyltin oxide hydroxides such as butyltinoxide hydroxide, aluminum alkoxides, alkyl zinc, dialkyl zinc, zincoxide, stannous oxide, or combinations thereof. Such catalysts may beutilized in amounts of, for example, from about 0.01 mole percent toabout 5 mole percent based on the starting diacid or diester used togenerate the polyester resin.

In embodiments, suitable amorphous resins include polyesters,polyamides, polyimides, polyolefins, polyethylene, polybutylene,polyisobutyrate, ethylene-propylene copolymers, ethylene-vinyl acetatecopolymers, polypropylene, combinations thereof, and the like. Examplesof amorphous resins which may be utilized include poly(styrene-acrylate)resins, crosslinked, for example, from about 10 percent to about 70percent, poly(styrene-acrylate) resins, poly(styrene-methacrylate)resins, crosslinked poly(styrene-methacrylate) resins,poly(styrene-butadiene) resins, crosslinked poly(styrene-butadiene)resins, alkali sulfonated-polyester resins, branched alkalisulfonated-polyester resins, alkali sulfonated-polyimide resins,branched alkali sulfonated-polyimide resins, alkali sulfonatedpoly(styrene-acrylate) resins, crosslinked alkali sulfonatedpoly(styrene-acrylate) resins, poly(styrene-methacrylate) resins,crosslinked alkali sulfonated-poly(styrene-methacrylate) resins, alkalisulfonated-poly(styrene-butadiene) resins, and crosslinked alkalisulfonated poly(styrene-butadiene) resins. Alkali sulfonated polyesterresins may be useful in embodiments, such as the metal or alkali saltsof copoly(ethylene-terephthalate)-copoly(ethylene-5-sulfo-isophthalate),copoly(propylene-terephthalate)-copoly(propylene-5-sulfo-isophthalate),copoly(diethylene-terephthalate)-copoly(diethylene-5-sulfo-isophthalate),copoly(propylene-diethylene-terephthalate)-copoly(propylene-diethylene-5-sulfoisophthalate),copoly(propylene-butylene-terephthalate)-copoly(propylene-butylene-5-sulfo-isophthalate),copoly(propoxylated bisphenol-A-fumarate)-copoly(propoxylated bisphenolA-5-sulfo-isophthalate), copoly(ethoxylatedbisphenol-A-fumarate)-copoly(ethoxylatedbisphenol-A-5-sulfo-isophthalate), and copoly(ethoxylatedbisphenol-A-maleate)-copoly(ethoxylatedbisphenol-A-5-sulfo-isophthalate), and wherein the alkali metal is, forexample, a sodium, lithium or potassium ion.

Examples of other suitable latex resins or polymers which may beutilized include, but are not limited to, poly(styrene-butadiene),poly(methylstyrene-butadiene), poly(methyl methacrylate-butadiene),poly(ethyl methacrylate-butadiene), poly(propyl methacrylate-butadiene),poly(butyl methacrylate-butadiene), poly(methyl acrylate-butadiene),poly(ethyl acrylate-butadiene), poly(propyl acrylate-butadiene),poly(butyl acrylate-butadiene), poly(styrene-isoprene),poly(methylstyrene-isoprene), poly(methyl methacrylate-isoprene),poly(ethyl methacrylate-isoprene), poly(propyl methacrylate-isoprene),poly(butyl methacrylate-isoprene), poly(methyl acrylate-isoprene),poly(ethyl acrylate-isoprene), poly(propyl acrylate-isoprene),poly(butyl acrylate-isoprene); poly(styrene-propyl acrylate),poly(styrene-butyl acrylate), poly(styrene-butadiene-acrylic acid),poly(styrene-butadiene-methacrylic acid),poly(styrene-butadiene-acrylonitrile-acrylic acid), poly(styrene-butylacrylate-acrylic acid), poly(styrene-butyl acrylate-methacrylic acid),poly(styrene-butyl acrylate-acrylonitrile), and poly(styrene-butylacrylate-acrylonitrile-acrylic acid), and combinations thereof. Thepolymer may be block, random, or alternating copolymers.

In embodiments, an unsaturated polyester resin may be utilized as alatex resin. Examples of such resins include those disclosed in U.S.Pat. No. 6,063,827, the disclosure of which is hereby incorporated byreference in its entirety. Exemplary unsaturated polyester resinsinclude, but are not limited to, poly(propoxylated bisphenolco-fumarate), poly(ethoxylated bisphenol co-fumarate),poly(butyloxylated bisphenol co-fumarate), poly(co-propoxylatedbisphenol co-ethoxylated bisphenol co-fumarate), poly(1,2-propylenefumarate), poly(propoxylated bisphenol co-maleate), poly(ethoxylatedbisphenol co-maleate), poly(butyloxylated bisphenol co-maleate),poly(co-propoxylated bisphenol co-ethoxylated bisphenol co-maleate),poly(1,2-propylene maleate), poly(propoxylated bisphenol co-itaconate),poly(ethoxylated bisphenol co-itaconate), poly(butyloxylated bisphenolco-itaconate), poly(co-propoxylated bisphenol co-ethoxylated bisphenolco-itaconate), poly(1,2-propylene itaconate), and combinations thereof.

in embodiments, a suitable polyester resin may be an amorphous polyestersuch as a poly(propoxylated bisphenol A co-fumarate) resin having thefollowing formula (I):

wherein m may be from about 5 to about 1000.

An example of a linear propoxylated bisphenol A fumarate resin which maybe utilized as a latex resin is available under the trade name SPARIIfrom Resana S/A Industrias Quimicas, Sao Paulo Brazil. Otherpropoxylated bisphenol A fumarate resins that may be utilized and arecommercially available include GTUF and FPESL-2 from Kao Corporation,Japan, and EM181635 from Reichhold, Research Triangle Park, NorthCarolina and the like.

Suitable crystalline resins include those disclosed in U.S. PatentApplication Publication No. 2006/0222991, the disclosure of which ishereby incorporated by reference in its entirety. In embodiments, asuitable crystalline resin may include a resin composed of ethyleneglycol and a mixture of dodecanedioic acid and fumaric acid co-monomerswith the following formula:

wherein b is from 5 to 2000 and d is from 5 to 2000.

For example, in embodiments, a poly(propoxylated bisphenol Aco-fumarate) resin of formula I as described above may be combined witha crystalline resin of formula II to form a core.

In embodiments, a resin utilized for forming the core may be partiallycrosslinked, which may be referred to, in embodiments, as a “partiallycrosslinked polyester resin” or a “polyester gel”. In embodiments, fromabout 1% by weight to about 50% by weight of the polyester gel may becrosslinked, in embodiments from about 5% by weight to about 35% byweight of the polyester gel may be crosslinked.

In embodiments, the amorphous resins described above may be partiallycrosslinked to form a core. For example, an amorphous resin which may becrosslinked and used in forming a toner particle in accordance with thepresent disclosure may include a crosslinked amorphous polyester offormula I above. Methods for forming the polyester gel include thosewithin the purview of those skilled in the art. For example,crosslinking may be achieved by combining an amorphous resin with acrosslinker, sometimes referred to herein, in embodiments, as aninitiator. Examples of suitable crosslinkers include, but are notlimited to, for example, free radical or thermal initiators such asorganic peroxides and azo compounds. Examples of suitable organicperoxides include diacyl peroxides such as, for example, decanoylperoxide, lauroyl peroxide and benzoyl peroxide, ketone peroxides suchas, for example, cyclohexanone peroxide and methyl ethyl ketone, alkylperoxyesters such as, for example, t-butyl peroxy neodecanoate,2,5-dimethyl 2,5-di(2-ethyl hexanoyl peroxy) hexane, t-amyl peroxy2-ethyl hexanoate, t-butyl peroxy 2-ethyl hexanoate, t-butyl peroxyacetate, t-amyl peroxy acetate, t-butyl peroxy benzoate, t-amyl peroxybenzoate, oo-t-butyl o-isopropyl mono peroxy carbonate, 2,5-dimethyl2,5-di(benzoyl peroxy) hexane, oo-t-butyl o-(2-ethyl hexyl) mono peroxycarbonate, and oo-t-amyl o-(2-ethyl hexyl) mono peroxy carbonate, alkylperoxides such as, for example, dicumyl peroxide, 2,5-dimethyl2,5-di(t-butyl peroxy) hexane, t-butyl cumyl peroxide, α-α-bis(t-butylperoxy)diisopropyl benzene, di-t-butyl peroxide and 2,5-dimethyl2,5-di(t-butyl peroxy) hexyne-3, alkyl hydroperoxides such as, forexample, 2,5-dihydro peroxy 2,5-dimethyl hexane, cumene hydroperoxide,t-butyl hydroperoxide and t-amyl hydroperoxide, and alkyl peroxyketalssuch as, for example, n-butyl 4,4-di(t-butyl peroxy) valerate,1,1-di(t-butyl peroxy) 3,3,5-trimethyl cyclohexane, 1,1-di(t-butylperoxy)cyclohexane, 1,1-di(t-amyl peroxy)cyclohexane, 2,2-di(t-butylperoxy) butane, ethyl 3,3-di(t-butyl peroxy) butyrate and ethyl3,3-di(t-amyl peroxy) butyrate, and combinations thereof. Examples ofsuitable azo compounds include 2,2,′-azobis(2,4-dimethylpentanenitrile), azobis-isobutyronitrile, 2,2′-azobis(isobutyronitrile),2,2′-azobis(2,4-dimethyl valeronitrile), 2,2′-azobis(methylbutyronitrile), 1,1′-azobis(cyano cyclohexane), other similar knowncompounds, and combinations thereof.

Although any suitable initiator can be used, in embodiments theinitiator may be an organic initiator that is soluble in any solventpresent, but not soluble in water. For example, half-life/temperaturecharacteristic plots for VAZO® 52 (2,2,′-azobis(2,4-dimethylpentanenitrile), commercially available from E. I. du Pont de Nemours andCompany, USA) shows a half-life greater than about 90 minutes at about65° C. and less than about 20 minutes at about 80° C.

Where utilized, the crosslinker may be present in an amount of fromabout 0.5% by weight to about 20% by weight of the resin, in embodimentsfrom about 1% by weight to about 10% by weight of the resin.

The crosslinker and amorphous resin may be combined for a sufficienttime and at a sufficient temperature to form the crosslinked polyestergel. In embodiments, the crosslinker and amorphous resin may be heatedto a temperature of from about 25° C. to about 99° C., in embodimentsfrom about 40° C. to about 95° C., for a period of time of from about 1minute to about 10 hours, in embodiments from about 5 minutes to about 5hours, to form a crosslinked polyester resin or polyester gel suitablefor use in forming toner particles.

In embodiments, the combined amorphous resins utilized in the core mayhave a glass transition temperature of from about 30° C. to about 80°C., in embodiments from about 35° C. to about 70° C. In furtherembodiments, the combined resins utilized in the core may have a meltviscosity of from about 10 to about 1,000,000 Pa*S at about 130° C., inembodiments from about 20 to about 100,000 Pa*S.

One, two, or more toner resins may be used. In embodiments where two ormore toner resins are used, the toner resins may be in any suitableratio (e.g., weight ratio) such as for instance about 10% (firstresin)/90% (second resin) to about 90% (first resin)/10% (second resin).

In embodiments, the resin may be formed by emulsion polymerizationmethods.

Toner

The resin described above may be utilized to form toner compositions.Such loner compositions may include optional colorants, waxes, and otheradditives. Toners may be formed utilizing any method within the purviewof those skilled in the art.

Surfactants

In embodiments, colorants, waxes, and other additives utilized to formtoner compositions may be in dispersions including surfactants.Moreover, toner particles may be formed by emulsion aggregation methodswhere the resin and other components of the toner are placed in one ormore surfactants, an emulsion is formed, toner particles are aggregated,coalesced, optionally washed and dried, and recovered.

One, two, or more surfactants may be utilized. The surfactants may beselected from ionic surfactants and nonionic surfactants. Anionicsurfactants and cationic surfactants are encompassed by the term “ionicsurfactants.” In embodiments, the surfactant may be utilized so that itis present in an amount of from about 0.01% to about 5% by weight of thetoner composition, for example from about 0.75% to about 4% by weight ofthe toner composition, in embodiments from about 1% to about 3% byweight of the toner composition.

Examples of nonionic surfactants that can be utilized include, forexample, polyacrylic acid, methalose, methyl cellulose, ethyl cellulose,propyl cellulose, hydroxy ethyl cellulose, carboxy methyl cellulose,polyoxyethylene cetyl ether, polyoxyethylene lauryl ether,polyoxyethylene octyl ether, polyoxyethylene octylphenyl ether,polyoxyethylene oleyl ether, polyoxyethylene sorbitan monolaurate,polyoxyethylene stearyl ether, polyoxyethylene nonylphenyl ether,dialkylphenoxy poly(ethyleneoxy)ethanol, available from Rhone-Poulenacas IGEPAL CA-210™, IGEPAL CA-520™, IGEPAL CA-720™, IGEPAL CO-890™,IGEPAL CO-720™, IGEPAL CO-290™, IGEPAL CA-21 ™, ANTAROX 890™ and ANTAROX897™. Other examples of suitable nonionic surfactants include a blockcopolymer of polyethylene oxide and polypropylene oxide, including thosecommercially available as SYNPERONIC PE/F, in embodiments SYNPERONICPE/F 108.

Anionic surfactants which may be utilized include sulfates andsulfonates, sodium dodecylsulfate (SDS), sodium dodecylbenzenesulfonate, sodium dodecylnaphthalene sulfate, dialkyl benzenealkylsulfates and sulfonates, acids such as abitic acid available fromAldrich, NEOGEN R™, NEOGEN SC™ obtained from Daiichi Kogyo Seiyaku,combinations thereof, and the like. Other suitable anionic surfactantsinclude, in embodiments, DOWFAX™ 2A1, an alkyldiphenyloxide disulfonatefrom The Dow Chemical Company, and/or TAYCA POWER BN2060 from TaycaCorporation (Japan), which are branched sodium dodecyl benzenesulfonates. Combinations of these surfactants and any of the foregoinganionic surfactants may be utilized in embodiments.

Examples of the cationic surfactants, which are usually positivelycharged, include, for example, alkylbenzyl dimethyl ammonium chloride,dialkyl benzenealkyl ammonium chloride, lauryl trimethyl ammoniumchloride, alkylbenzyl methyl ammonium chloride, alkyl benzyl dimethylammonium bromide, benzalkonium chloride, cetyl pyridinium bromide, C₁₂,C₁₅, C₁₇ trimethyl ammonium bromides, halide salts of quaternizedpolyoxyethylalkylamines, dodecylbenzyl triethyl ammonium chloride,MIRAPOL™ and ALKAQUAT™, available from Alkaril Chemical Company,SANIZOL™ (benzalkonium chloride), available from Kao Chemicals, and thelike, and mixtures thereof.

Colorants

As the colorant to be added, various known suitable colorants, such asdyes, pigments, mixtures of dyes, mixtures of pigments, mixtures of dyesand pigments, and the like, may be included in the toner. The colorantmay be included in the toner in an amount of, for example, about 0.1 toabout 35 percent by weight of the toner, or from about 1 to about 15weight percent of the toner, or from about 3 to about 10 percent byweight of the toner.

As examples of suitable colorants, mention may be made of carbon blacklike REGAL 330®; magnetites, such as Mobay magnetites MO8029™, MO8060™;Columbian magnetites; MAPICO BLACKS™ and surface treated magnetites;Pfizer magnetites CB4799™, CB5300™, CB5600™, MCX6369™; Bayer magnetites,BAYFERROX 8600™, 8610™; Northern Pigments magnetites, NP-604™, NP-608™;Magnox magnetites TMB-100™, or TMB-104™; and the like. As coloredpigments, there can be selected cyan, magenta, yellow, red, green,brown, blue or mixtures thereof. Generally, cyan, magenta, or yellowpigments or dyes, or mixtures thereof, are used. The pigment or pigmentsare generally used as water based pigment dispersions.

Specific examples of pigments include SUNSPERSE 6000, FLEXIVERSE andAQUATONE water based pigment dispersions from SUN Chemicals, HELIOGENBLUE L6900™, D6840™, D7080™, D7020™, PYLAM OIL BLUE™, PYLAM OIL YELLOW™,PIGMENT BLUE 1™ available from Paul Uhlich & Company, Inc., PIGMENTVIOLET 1™, PIGMENT RED 48™, LEMON CHROME YELLOW DCC 1026™, E.D.TOLUIDINE RED™ and BON RED C™ available from Dominion Color Corporation,Ltd., Toronto, Ontario, NOVAPERM YELLOW FGL™, HOSTAPERM PINK E™ fromHoechst, and CINQUASIA MAGENTA™ available from E.I. DuPont de Nemours &Company, and the like. Generally, colorants that can be selected areblack, cyan, magenta, or yellow, and mixtures thereof. Examples ofmagentas are 2,9-dimethyl-substituted quinacridone and anthraquinone dyeidentified in the Color Index as CI 60710, CI Dispersed Red 15, diazodye identified in the Color Index as CI 26050, CI Solvent Red 19, andthe like. Illustrative examples of cyans include copper tetra(octadecylsulfonamido) phthalocyanine, x-copper phthalocyanine pigment listed inthe Color Index as CI 74160, CI Pigment Blue, Pigment Blue 15:3, andAnthrathrene Blue, identified in the Color Index as CI 69810, SpecialBlue X-2137, and the like. Illustrative examples of yellows arediarylide yellow 3,3-dichlorobenzidene acetoacetanilides, a monoazopigment identified in the Color Index as CI 12700, CI Solvent Yellow 16,a nitrophenyl amine sulfonamide identified in the Color Index as ForonYellow SE/GLN, CI Dispersed Yellow 33 2,5-dimethoxy-4-sulfonanilidephenylazo-4′-chloro-2,5-dimethoxy acetoacetanilide, and Permanent YellowFGL. Colored magnetites, such as mixtures of MAPICO BLACK™, and cyancomponents may also be selected as colorants. Other known colorants canbe selected, such as Levanyl Black A-SF (Miles, Bayer) and SunsperseCarbon Black LHD 9303 (Sun Chemicals), and colored dyes such as NeopenBlue (BASF), Sudan Blue OS (BASF), PV Fast Blue B2G01 (AmericanHoechst), Sunsperse Blue BHD 6000 (Sun Chemicals), Irgalite Blue BCA(Ciba-Geigy), Paliogen Blue 6470 (BASF), Sudan III (Matheson, Coleman,Bell), Sudan II (Matheson, Coleman, Bell), Sudan IV (Matheson, Coleman,Bell), Sudan Orange G (Aldrich), Sudan Orange 220 (BASF), PaliogenOrange 3040 (BASF), Ortho Orange OR 2673 (Paul Uhlich), Paliogen Yellow152, 1560 (BASF), Lithol Fast Yellow 0991K (BASF), Paliotol Yellow 1840(BASF), Neopen Yellow (BASF), Novoperm Yellow FG 1 (Hoechst), PermanentYellow YE 0305 (Paul Uhlich), Lumogen Yellow D0790 (BASF), SunsperseYellow YHD 6001 (Sun Chemicals), Suco-Gelb L1250 (BASF), Suco-Yellow DI355 (BASF), Hostaperm Pink E (American Hoechst), Fanal Pink D4830(BASF), Cinquasia Magenta (DuPont), Lithol Scarlet D3700 (BASF),Toluidine Red (Aldrich), Scarlet for Thermoplast NSD PS PA (UgineKuhlmann of Canada), E.D. Toluidine Red (Aldrich), Lithol Rubine Toner(Paul Uhlich), Lithol Scarlet 4440 (BASF), Bon Red C (Dominion ColorCompany), Royal Brilliant Red RD-8192 (Paul Uhlich), Oracet Pink RF(Ciba-Geigy), Paliogen Red 3871K (BASF), Paliogen Red 3340 (BASF),Lithol Fast Scarlet L4300 (BASF), combinations of the foregoing, and thelike.

Wax

Optionally, a wax may also be combined with the resin and optionalcolorant in forming toner particles. When included, the wax may bepresent in an amount of, for example, from about 1 weight percent toabout 25 weight percent of the toner particles, in embodiments fromabout 5 weight percent to about 20 weight percent of the tonerparticles.

Waxes that may be selected include waxes having, for example, a weightaverage molecular weight of from about 500 to about 20,000, inembodiments from about 1,000 to about 10,000. Waxes that may be usedinclude, for example, polyolefins such as polyethylene, polypropylene,and polybutene waxes such as commercially available from Allied Chemicaland Petrolite Corporation, for example POLYWAX™ polyethylene waxes fromBaker Petrolite, wax emulsions available from Michaelman, Inc. and theDaniels Products Company, EPOLENE N-15™ commercially available fromEastman Chemical Products, Inc., and VISCOL 550-P™, a low weight averagemolecular weight polypropylene available from Sanyo Kasei K. K.;plant-based waxes, such as carnauba wax, rice wax, candelilla wax,sumacs wax, and jojoba oil; animal-based waxes, such as beeswax;mineral-based waxes and petroleum-based waxes, such as montan wax,ozokerite, ceresin, paraffin wax, microcrystalline wax, andFischer-Tropsch wax; ester waxes obtained from higher fatty acid andhigher alcohol, such as stearyl stearate and behenyl behenate; esterwaxes obtained from higher fatty acid and monovalent or multivalentlower alcohol, such as butyl stearate, propyl oleate, glyceridemonostearate, glyceride distearate, and pentaerythritol tetra behenate;ester waxes obtained from higher fatty acid and multivalent alcoholmultimers, such as diethyleneglycol monostearate, dipropyleneglycoldistearate, diglyceryl distearate, and triglyceryl tetrastearate;sorbitan higher fatty acid ester waxes, such as sorbitan monostearate,and cholesterol higher fatty acid ester waxes, such as cholesterylstearate. Examples of functionalized waxes that may be used include, forexample, amines, amides, for example AQUA SUPERSLIP 6550™, SUPERSLIP6530™ available from Micro Powder Inc., fluorinated waxes, for examplePOLYFLUO 190™, POLYFLUO 200™, POLYSILK 19™, POLYSILK 14™ available fromMicro Powder Inc., mixed fluorinated, amide waxes, for exampleMICROSPERSION 19™ also available from Micro Powder Inc., imides, esters,quaternary amines, carboxylic acids or acrylic polymer emulsion, forexample JONCRYL 74™, 89™, 130™, 537™, and 538™, all available from SCJohnson Wax, and chlorinated polypropylenes and polyethylenes availablefrom Allied Chemical and Petrolite Corporation and SC Johnson wax.Mixtures and combinations of the foregoing waxes may also be used inembodiments. Waxes may be included as, for example, fuser roll releaseagents.

Toner Preparation

The toner particles may be prepared by any method within the purview ofone skilled in the art. Although embodiments relating to toner particleproduction are described below with respect to emulsion-aggregationprocesses, any suitable method of preparing toner particles may be used,including chemical processes, such as suspension and encapsulationprocesses disclosed in U.S. Pat. Nos. 5,290,654 and 5,302,486, thedisclosures of each of which are hereby incorporated by reference intheir entirety. In embodiments, toner compositions and toner particlesmay be prepared by aggregation and coalescence processes in whichsmall-size resin particles are aggregated to the appropriate tonerparticle size and then coalesced to achieve the final toner particleshape and morphology.

In embodiments, toner compositions may be prepared byemulsion-aggregation processes, such as a process that includesaggregating a mixture of an optional colorant, an optional wax and anyother desired or required additives, and emulsions including the resinsdescribed above, optionally in surfactants as described above, and thencoalescing the aggregate mixture. A mixture may be prepared by adding acolorant and optionally a wax or other materials, which may also beoptionally in a dispersion(s) including a surfactant, to the emulsion,which may be a mixture of two or more emulsions containing the resin.The pH of the resulting mixture may be adjusted by an acid such as, forexample, acetic acid, nitric acid or the like. In embodiments, the pH ofthe mixture may be adjusted to from about 4 to about 5. Additionally, inembodiments, the mixture may be homogenized. If the mixture ishomogenized, homogenization may be accomplished by mixing at about 600to about 4,000 revolutions per minute. Homogenization may beaccomplished by any suitable means, including, for example, an IKA ULTRATURRAX T50 probe homogenizer.

Following the preparation of the above mixture, an aggregating agent maybe added to the mixture. Any suitable aggregating agent may be utilizedto form a toner. Suitable aggregating agents include, for example,aqueous solutions of a divalent cation or a multivalent cation material.The aggregating agent may be, for example, polyaluminum halides such aspolyaluminum chloride (PAC), or the corresponding bromide, fluoride, oriodide, polyaluminum silicates such as polyaluminum sulfosilicate(PASS), and water soluble metal salts including aluminum chloride,aluminum nitrite, aluminum sulfate, potassium aluminum sulfate, calciumacetate, calcium chloride, calcium nitrite, calcium oxylate, calciumsulfate, magnesium acetate, magnesium nitrate, magnesium sulfate, zincacetate, zinc nitrate, zinc sulfate, zinc chloride, zinc bromide,magnesium bromide, copper chloride, copper sulfate, and combinationsthereof. In embodiments, the aggregating agent may be added to themixture at a temperature that is below the glass transition temperature(Tg) of the resin.

The aggregating agent may be added to the mixture utilized to form atoner in an amount of, for example, from about 0.1% to about 8% byweight, in embodiments from about 0.2% to about 5% by weight, in otherembodiments from about 0.5% to about 5% by weight, of the resin in themixture. This provides a sufficient amount of agent for aggregation.

In order to control aggregation and subsequent coalescence of theparticles, in embodiments the aggregating agent may be metered into themixture over time. For example, the agent may be metered into themixture over a period of from about 5 to about 240 minutes, inembodiments from about 30 to about 200 minutes, although more or lesstime may be used as desired or required. The addition of the agent mayalso be done while the mixture is maintained under stirred conditions,in embodiments from about 50 rpm to about 1,000 rpm, in otherembodiments from about 100 rpm to about 500 rpm, and at a temperaturethat is below the glass transition temperature of the resin as discussedabove, in embodiments from about 30° C. to about 90° C., in embodimentsfrom about 35° C. to about 70° C.

The particles may be permitted to aggregate until a predetermineddesired particle size is obtained. A predetermined desired size refersto the desired particle size to be obtained as determined prior toformation, and the particle size being monitored during the growthprocess until such particle size is reached. Samples may be taken duringthe growth process and analyzed, for example with a Coulter Counter, foraverage particle size. The aggregation thus may proceed by maintainingthe elevated temperature, or slowly raising the temperature to, forexample, from about 30° C. to about 99° C., and holding the mixture atthis temperature for a time from about 0.5 hours to about 10 hours, inembodiments from about hour 1 to about 5 hours, while maintainingstirring, to provide the aggregated particles. Once the predetermineddesired particle size is reached, then the growth process is halted. Inembodiments, the predetermined desired particle size is within the tonerparticle size ranges mentioned above.

The growth and shaping of the particles following addition of theaggregation agent may be accomplished under any suitable conditions. Forexample, the growth and shaping may be conducted under conditions inwhich aggregation occurs separate from coalescence. For separateaggregation and coalescence stages, the aggregation process may beconducted under shearing conditions at an elevated temperature, forexample of from about 40° C. to about 90° C., in embodiments from about45° C. to about 80° C., which may be below the glass transitiontemperature of the resin as discussed above.

Once the desired final size of the toner particles is achieved, the pHof the mixture may be adjusted with a base to a value of from about 3 toabout 10, and in embodiments from about 5 to about 9. The adjustment ofthe pH may be utilized to freeze, that is to stop, toner growth. Thebase utilized to stop toner growth may include any suitable base suchas, for example, alkali metal hydroxides such as, for example, sodiumhydroxide, potassium hydroxide, ammonium hydroxide, combinationsthereof, and the like. In embodiments, ethylene diamine tetraacetic acid(EDTA) may be added to help adjust the pH to the desired values notedabove.

Shell Resin

In embodiments, after aggregation, but prior to coalescence, a shell maybe applied to the aggregated particles. In embodiments, a resin utilizedfor forming the shell may be partially crosslinked, which may bereferred to, in embodiments, as a “partially crosslinked polyesterresin” or a “polyester gel”. The crosslinked portion of the gel can bedetermined by any suitable method within the purview of those skilled inthe art, for example, the gel can be dissolved in a suitable solvent,such as, toluene, then the weight of the insolubles may be measured.

In embodiments, from about 1% by weight to about 50% by weight of theshell resin may be crosslinked, in embodiments from about 5% by weightto about 35% by weight of the shell resin may be crosslinked.

Resins which may be utilized to form a polyester gel as a shell include,but are not limited to, the amorphous resins described above for use inthe core. In embodiments, an amorphous resin which may be crosslinkedand used as a polyester gel to form a shell in accordance with thepresent disclosure may include a crosslinked amorphous polyester offormula I above. Methods for forming the polyester gel include thosewithin the purview of those skilled in the art. For example,crosslinking may be achieved by combining an amorphous resin with acrosslinker, sometimes referred to herein, in embodiments, as aninitiator. Examples of suitable crosslinkers include, but are notlimited to, for example free radical or thermal initiators such asorganic peroxides and azo compounds described above as suitable forforming a gel in the core. Examples of suitable organic peroxidesinclude diacyl peroxides such as, for example, decanoyl peroxide,lauroyl peroxide and benzoyl peroxide, ketone peroxides such as, forexample, cyclohexanone peroxide and methyl ethyl ketone, alkylperoxyesters such as, for example, t-butyl peroxy neodecanoate,2,5-dimethyl 2,5-di(2-ethyl hexanoyl peroxy) hexane, t-amyl peroxy2-ethyl hexanoate, t-butyl peroxy 2-ethyl hexanoate, t-butyl peroxyacetate, t-amyl peroxy acetate, t-butyl peroxy benzoate, t-amyl peroxybenzoate, oo-t-butyl o-isopropyl mono peroxy carbonate, 2,5-dimethyl2,5-di(benzoyl peroxy) hexane, oo-t-butyl o-(2-ethyl hexyl) mono peroxycarbonate, and oo-t-amyl o-(2-ethyl hexyl) mono peroxy carbonate, alkylperoxides such as, for example, dicumyl peroxide, 2,5-dimethyl2,5-di(t-butyl peroxy) hexane, t-butyl cumyl peroxide, α-α-bis(t-butylperoxy)diisopropyl benzene, di-t-butyl peroxide and 2,5-dimethyl2,5-di(t-butyl peroxy) hexyne-3, alkyl hydroperoxides such as, forexample, 2,5-dihydro peroxy 2,5-dimethyl hexane, cumene hydroperoxide,t-butyl hydroperoxide and t-amyl hydroperoxide, and alkyl peroxyketalssuch as, for example, n-butyl 4,4-di(t-butyl peroxy) valerate,1,1-di(t-butyl peroxy) 3,3,5-trimethyl cyclohexane, 1,1-di(t-butylperoxy)cyclohexane, 1,1-di(t-amyl peroxy)cyclohexane, 2,2-di(t-butylperoxy) butane, ethyl 3,3-di(t-butyl peroxy) butyrate and ethyl3,3-di(t-amyl peroxy) butyrate, and combinations thereof. Examples ofsuitable azo compounds include 2,2,′-azobis(2,4-dimethylpentanenitrile), azobis-isobutyronitrile, 2,2′-azobis(isobutyronitrile),2,2′-azobis(2,4-dimethyl valeronitrile), 2,2′-azobis(methylbutyronitrile), 1,1′-azobis(cyano cyclohexane), other similar knowncompounds, and combinations thereof.

Although any suitable initiator can be used, in embodiments theinitiator may be an organic initiator that is soluble in any solventpresent, but not soluble in water. For example, half-life/temperaturecharacteristic plots for VAZO® 52 (2,2,′-azobis(2,4-dimethylpentanenitrile), commercially available from E. I. du Pont de Nemours andCompany, USA) shows a half-life greater than about 90 minutes at about65° C. and less than about 20 minutes at about 80° C.

Where utilized, the crosslinker may be present in an amount of fromabout 0.5% by weight to about 20% by weight of the resin, in embodimentsfrom about 1% by weight to about 10% by weight of the resin.

The crosslinker and amorphous resin may be combined for a sufficienttime and at a sufficient temperature to form the crosslinked polyestergel. In embodiments, the crosslinker and amorphous resin may be heatedto a temperature of from about 25° C. to about 99° C., in embodimentsfrom about 30° C. to about 95° C., for a period of time of from about 1minute to about 10 hours, in embodiments from about 5 minutes to about 5hours, to form a crosslinked polyester resin or polyester gel suitablefor use as a shell.

A single crosslinked polyester resin may be utilized as the shell or, inembodiments, a first crosslinked polyester resin may be combined withother resins to form a shell. For example, in embodiments, a crosslinkedamorphous resin may be combined with additional amorphous resins to forma polyester gel shell. Multiple resins may be utilized in any suitableamounts. In embodiments, a first crosslinked amorphous polyester resin,for example a crosslinked amorphous resin of formula I above, may bepresent in an amount of from about 20 percent by weight to about 100percent by weight of the total shell resin, in embodiments from about 30percent by weight to about 90 percent by weight of the total shellresin. Thus, in embodiments, a second resin may be present in the shellresin in an amount of from about 0 percent by weight to about 80 percentby weight of the total shell resin, in embodiments from about 10 percentby weight to about 70 percent by weight of the shell resin.

The crosslinked shell resin may be applied to the aggregated particlesby any method within the purview of those skilled in the art. Inembodiments, the crosslinked polyester resin utilized to form the shellmay be combined with a surfactant described above to form an emulsion.The emulsion possessing the crosslinked polyester resin may be combinedwith the aggregated particles described above so that the shell formsover the aggregated particles. Where the gel is in an emulsion, the gelemulsion may possess from about 1 percent solids by weight of theemulsion to about 80 percent solids by weight of the emulsion, inembodiments from about 5 percent solids by weight of the emulsion toabout 60 percent solids by weight of the emulsion.

The formation of the shell over the aggregated particles may occur whileheating to an elevated temperature in embodiments from about 35° C. toabout 99° C., in embodiments from about 40° C. to about 80° C. Theformation of the shell may take place for a period of time of from about1 minute to about 5 hours, in embodiments from about 5 minutes to about3 hours.

Utilizing the polyester gel to form a shell permits the use of hightemperatures in formation of the shell and the subsequent coalescence ofthe toner particles, thereby expanding the process latitude whilepreventing the crystalline polyester from migrating to the surface ofthe toner particles.

Coalescence

Following aggregation to the desired particle size and application ofthe shell resin described above, the particles may then be coalesced tothe desired final shape, the coalescence being achieved by, for example,heating the mixture to a suitable temperature. This temperature may, inembodiments, be from about 0° C. to about 50° C. higher than the onsetmelting point of the crystalline polyester resin utilized in the core,in other embodiments from about 5° C. to about 30° C. higher than theonset melting point of the crystalline polyester resin utilized in thecore. For example, by utilizing the polyester gel in forming a shell asdescribed above, in embodiments the temperature for coalescence may befrom about 40° C. to about 99° C., in embodiments from about 50° C. toabout 95° C. Higher or lower temperatures may be used, it beingunderstood that the temperature is a function of the resins used.

Coalescence may also be carried out with stirring, for example at aspeed of from about 50 rpm to about 1,000 rpm, in embodiments from about100 rpm to about 600 rpm. Coalescence may be accomplished over a periodof from about 1 minute to about 24 hours, in embodiments from about 5minutes to about 10 hours.

After coalescence, the mixture may be cooled to room temperature, suchas from about 20° C. to about 25° C. The cooling may be rapid or slow,as desired. A suitable cooling method may include introducing cold waterto a jacket around the reactor. After cooling, the toner particles maybe optionally washed with water, and then dried. Drying may beaccomplished by any suitable method for drying including, for example,freeze-drying.

As the polyester resin utilized to form the shell is a gel, the shellresin may be able to prevent any crystalline resin in the core frommigrating to the toner surface. In addition, the shell resin may be lesscompatible with the crystalline resin utilized in forming the core,which may result in a higher toner glass transition temperature (Tg).For example, toner particles having a shell of the present disclosuremay have a glass transition temperature of from about 30° C. to about80° C., in embodiments from about 35° C. to about 70° C. This higher Tgmay, in embodiments, improve blocking and charging characteristics ofthe toner particles, including A-zone charging.

The gel utilized to form the shell may also have a high viscosity offrom about 10,000,000 Poise to about 50,000,000 Poise, at coalescencetemperature, for example from about 60° C. to about 90° C., inembodiments from about 65° C. to about 80° C., which may also play arole in preventing crystalline resin in the core from migrating to thetoner surface, and thus improving A-zone charging. As the polyesterresin utilized to form the shell is crosslinked and in the form of agel, the shell resin may be able to prevent any crystalline resin in thecore from migrating to the toner surface.

Moreover, toners of the present disclosure having a gel in the shell mayexhibit excellent document offset performance characteristics, as wellas reduced peak gloss, in embodiments from about 20 Gardner gloss units(ggu) to about 100 ggu, in other embodiments from about 40 ggu to about80 ggu, which may be desirable for reproduction of text and images, assome users object to high gloss and the differential which may occurbetween low gloss and high gloss. While not wishing to be bound by anytheory, the reduction in peak gloss may be due to the higher viscosityof the toner compositions, which as noted above, may be due to thehigher viscosity of the gel utilized in forming the shell. Toners of thepresent disclosure also have excellent crease MFT properties.

In embodiments, the polyester gel utilized to form the shell may bepresent in an amount of from about 2 percent by weight to about 40percent by weight of the dry toner particles, in embodiments from about5 percent by weight to about 35 percent by weight of the dry tonerparticles.

Additives

In embodiments, the toner particles may also contain other optionaladditives, as desired or required. For example, the toner may includepositive or negative charge control agents, for example in an amount offrom about 0.1 to about 10 percent by weight of the toner, inembodiments from about 1 to about 3 percent by weight of the toner.Examples of suitable charge control agents include quaternary ammoniumcompounds inclusive of alkyl pyridinium halides; bisulfates; alkylpyridinium compounds, including those disclosed in U.S. Pat. No.4,298,672, the disclosure of which is hereby incorporated by referencein its entirety; organic sulfate and sulfonate compositions, includingthose disclosed in U.S. Pat. No. 4,338,390, the disclosure of which ishereby incorporated by reference in its entirety; cetyl pyridiniumtetrafluoroborates; distearyl dimethyl ammonium methyl sulfate; aluminumsalts such as BONTRON E84™ or E88™ (Hodogaya Chemical); combinationsthereof, and the like. Such charge control agents may be appliedsimultaneously with the shell resin described above or after applicationof the shell resin.

There can also be blended with the toner particles external additiveparticles including flow aid additives, which additives may be presenton the surface of the toner particles. Examples of these additivesinclude metal oxides such as titanium oxide, silicon oxide, tin oxide,mixtures thereof, and the like; colloidal and amorphous silicas, such asAEROSIL®, metal salts and metal salts of fatty acids inclusive of zincstearate, aluminum oxides, cerium oxides, and mixtures thereof. Each ofthese external additives may be present in an amount of from about 0.1percent by weight to about 5 percent by weight of the toner, inembodiments of from about 0.25 percent by weight to about 3 percent byweight of the toner. Suitable additives include those disclosed in U.S.Pat. Nos. 3,590,000, 3,800,588, and 6,214,507, the disclosures of eachof which are hereby incorporated by reference in their entirety. Again,these additives may be applied simultaneously with the shell resindescribed above or after application of the shell resin.

In embodiments, toners of the present disclosure may be utilized asultra low melt (ULM) toners. In embodiments, the dry toner particleshaving a shell of the present disclosure may, exclusive of externalsurface additives, have the following characteristics:

(1) Volume average diameter (also referred to as “volume averageparticle diameter”) of from about 3 to about 25 μm, in embodiments fromabout 4 to about 15 μm, in other embodiments from about 5 to about 12μm.

(2) Number Average Geometric Size Distribution (GSDn) and/or VolumeAverage Geometric Size Distribution (GSDv) of from about 1.05 to about1.55, in embodiments from about 1.1 to about 1.4.

(3) Circularity of from about 0.93 to about 1, in embodiments from about0.95 to about 0.99 (measured with, for example, a Sysmex FPIA 2100analyzer).

The characteristics of the toner particles may be determined by anysuitable technique and apparatus. Volume average particle diameterD_(50v), GSDv, and GSDn may be measured by means of a measuringinstrument such as a Beckman Coulter Multisizer 3, operated inaccordance with the manufacturer's instructions. Representative samplingmay occur as follows: a small amount of toner sample, about 1 gram, maybe obtained and filtered through a 25 micrometer screen, then put inisotonic solution to obtain a concentration of about 10%, with thesample then run in a Beckman Coulter Multisizer 3.

Toners produced in accordance with the present disclosure may possessexcellent charging characteristics when exposed to extreme relativehumidity (RH) conditions. The low-humidity zone (C zone) may be about10° C./15% RH, while the high humidity zone (A zone) may be about 28°C./85% RH. Toners of the present disclosure may possess A zone chargingof from about −3 μC/g to about −35 μC/g, in embodiments from about −4μC/g to about −30 μC/g, a parent toner charge per mass ratio (Q/M) offrom about −3 μC/g to about −35 μC/g, in embodiments from about −4 μC/gto about −30 μC/g, and a final triboelectric charge of from −10 μC/g toabout −45 μC/g, in embodiments from about −12 μC/g to about −40 μC/g.

In accordance with the present disclosure, the charging of the tonerparticles may be enhanced, so less surface additives may be required,and the final toner charging may thus be higher to meet machine chargingrequirements.

Developers

The toner particles thus obtained may be formulated into a developercomposition. The toner particles may be mixed with carrier particles toachieve a two-component developer composition. The toner concentrationin the developer may be from about 1% to about 25% by weight of thetotal weight of the developer, in embodiments from about 2% to about 15%by weight of the total weight of the developer.

Carriers

Examples of carrier particles that can be utilized for mixing with thetoner include those particles that are capable of triboelectricallyobtaining a charge of opposite polarity to that of the toner particles.Illustrative examples of suitable carrier particles include granularzircon, granular silicon, glass, steel, nickel, ferrites, iron ferrites,silicon dioxide, and the like. Other carriers include those disclosed inU.S. Pat. Nos. 3,847,604, 4,937,166, and 4,935,326.

The selected carrier particles can be used with or without a coating. Inembodiments, the carrier particles may include a core with a coatingthereover which may be formed from a mixture of polymers that are not inclose proximity thereto in the triboelectric series. The coating mayinclude fluoropolymers, such as polyvinylidene fluoride resins,terpolymers of styrene, methyl methacrylate, and/or silanes, such astriethoxy silane, tetrafluoroethylenes, other known coatings and thelike. For example, coatings containing polyvinylidenefluoride,available, for example, as KYNAR 301F™, and/or polymethylmethacrylate,for example having a weight average molecular weight of about 300,000 toabout 350,000, such as commercially available from Soken, may be used.In embodiments, polyvinylidenefluoride and polymethylmethacrylate (PMMA)may be mixed in proportions of from about 30 to about 70 weight % toabout 70 to about 30 weight %, in embodiments from about 40 to about 60weight % to about 60 to about 40 weight %. The coating may have acoating weight of, for example, from about 0.1 to about 5% by weight ofthe carrier, in embodiments from about 0.5 to about 2% by weight of thecarrier.

In embodiments, PMMA may optionally be copolymerized with any desiredcomonomer, so long as the resulting copolymer retains a suitableparticle size. Suitable comonomers can include monoalkyl, or dialkylamines, such as a dimethylaminoethyl methacrylate, diethylaminoethylmethacrylate, diisopropylaminoethyl methacrylate, or t-butylaminoethylmethacrylate, and the like. The carrier particles may be prepared bymixing the carrier core with polymer in an amount from about 0.05 toabout 10 percent by weight, in embodiments from about 0.01 percent toabout 3 percent by weight, based on the weight of the coated carrierparticles, until adherence thereof to the carrier core by mechanicalimpaction and/or electrostatic attraction.

Various effective suitable means can be used to apply the polymer to thesurface of the carrier core particles, for example, cascade roll mixing,tumbling, milling, shaking, electrostatic powder cloud spraying,fluidized bed, electrostatic disc processing, electrostatic curtain,combinations thereof, and the like. The mixture of carrier coreparticles and polymer may then be heated to enable the polymer to meltand fuse to the carrier core particles. The coated carrier particles maythen be cooled and thereafter classified to a desired particle size.

In embodiments, suitable carriers may include a steel core, for exampleof from about 25 to about 100 μm in size, in embodiments from about 50to about 75 μm in size, coated with about 0.5% to about 10% by weight,in embodiments from about 0.7% to about 5% by weight, of a conductivepolymer mixture including, for example, methylacrylate and carbon blackusing the process described in U.S. Pat. Nos. 5,236,629 and 5,330,874.

The carrier particles can be mixed with the toner particles in varioussuitable combinations. The concentrations are may be from about 1% toabout 20% by weight of the toner composition. However, different tonerand carrier percentages may be used to achieve a developer compositionwith desired characteristics.

Imaging

The toners can be utilized for electrostatographic or xerographicprocesses, including those disclosed in U.S. Pat. No. 4,295,990, thedisclosure of which is hereby incorporated by reference in its entirety.In embodiments, any known type of image development system may be usedin an image developing device, including, for example, magnetic brushdevelopment, jumping single-component development, hybrid scavengelessdevelopment (HSD), and the like. These and similar development systemsare within the purview of those skilled in the art.

Imaging processes include, for example, preparing an image with axerographic device including a charging component, an imaging component,a photoconductive component, a developing component, a transfercomponent, and a fusing component. In embodiments, the developmentcomponent may include a developer prepared by mixing a carrier with atoner composition described herein. The xerographic device may include ahigh speed printer, a black and white high speed printer, a colorprinter, and the like.

Once the image is formed with toners/developers via a suitable imagedevelopment method such as any one of the aforementioned methods, theimage may then be transferred to an image receiving medium such as paperand the like. In embodiments, the toners may be used in developing animage in an image-developing device utilizing a fuser roll member. Fuserroll members are contact fusing devices that are within the purview ofthose skilled in the art, in which heat and pressure from the roll maybe used to fuse the toner to the image-receiving medium. In embodiments,the fuser member may be heated to a temperature above the fusingtemperature of the toner, for example to temperatures of from about 70°C. to about 160° C., in embodiments from about 80° C. to about 150° C.,in other embodiments from about 90° C. to about 140° C., after or duringmelting onto the image receiving substrate.

In embodiments where the toner resin is crosslinkable, such crosslinkingmay be accomplished in any suitable manner. For example, the toner resinmay be crosslinked during fusing of the toner to the substrate where thetoner resin is crosslinkable at the fusing temperature. Crosslinkingalso may be effected by heating the fused image to a temperature atwhich the toner resin will be crosslinked, for example in a post-fusingoperation. In embodiments, crosslinking may be effected at temperaturesof from about 160° C. or less, in embodiments from about 70° C. to about160° C., in other embodiments from about 80° C. to about 140° C.

The following Examples are being submitted to illustrate embodiments ofthe present disclosure. These Examples are intended to be illustrativeonly and are not intended to limit the scope of the present disclosure.Also, parts and percentages are by weight unless otherwise indicated. Asused herein, “room temperature” refers to a temperature of from about20° C. to about 25° C.

EXAMPLES Comparative Example 1

About 397.99 grams of a linear amorphous resin in an emulsion (about17.03 weight % resin) was added to a 2 liter beaker. The linearamorphous resin was of the following formula:

wherein m was from about 5 to about 1000 and was produced following theprocedures described in U.S. Pat. No. 6,063,827, the disclosure of whichis hereby incorporated by reference in its entirety. About 74.27 gramsof an unsaturated crystalline polyester (“UCPE”) resin composed ofethylene glycol and a mixture of dodecanedioic acid and fumaric acidco-monomers with the following formula:

wherein b is from 5 to 2000 and d is from 5 to 2000 in an emulsion(about 19.98 weight % resin), synthesized following the proceduresdescribed in U.S. Patent Application Publication No. 2006/0222991, thedisclosure of which is hereby incorporated by reference in its entirety,and about 29.24 grams of a cyan pigment, Pigment Blue 15:3, (about 17weight %) was added to the beaker. About 36 grams of Al₂(SO₄)₃ (about 1weight %) was added as flocculent under homogenization by mixing themixture at about 3000 to 4000 rpm.

The mixture was subsequently transferred to a 2 liter Buchi reactor, andheated to about 45.9° C. for aggregation and mixed at a speed of about750 rpm. The particle size was monitored with a Coulter Counter untilthe size of the particles reached an average volume particle size ofabout 6.83 μm with a Geometric Size Distribution (“GSD”) of about 1.21.

About 198.29 grams of the above emulsion with the resin of formula I wasthen added to the particles to form a shell thereover, resulting inparticles possessing a core/shell structure with an average particlesize of about 8.33 μm, and a GSD of about 1.21.

Thereafter, the pH of the reaction slurry was increased to about 6.7 byadding NaOH followed by the addition of about 0.45 pph EDTA (based ondry toner) to freeze, that is stop, the toner growth. After stopping thetoner growth, the reaction mixture was heated to about 69° C. and keptat that temperature for about 1 hour for coalescence.

The resulting toner particles had a final average volume particle sizeof about 8.07, a GSD of about 1.22, and a circularity of about 0.976.

The toner slurry was then cooled to room temperature, separated bysieving (utilizing a 25 μm sieve) and filtered, followed by washing andfreeze drying.

Example 1

A gel latex was prepared as follows. About 125 grams of the amorphouspropoxylated bisphenol A fumarate resin of formula I as described inComparative Example 1 above, with an acid number of about 17 as measuredby titration with KOH, was combined with about 3.75 grams of VAZO® 52free radical thermal initiator (E. I. du Pont de Nemours and Company,USA) in a 2 liter beaker containing about 919 grams of ethyl acetate.The mixture was stirred at about 250 revolutions per minute (rpm) andheated to about 67° C. to dissolve the resin and initiator in the ethylacetate.

About 4.37 grams of sodium bicarbonate and about 1.34 grams (46.8 wt %)of DOWFAX™ 2A1, an alkyldiphenyloxide disulfonate (from The Dow ChemicalCompany, Midland, Mich.), were measured into a 4 liter Pyrex glass flaskreactor containing about 708 grams of deionized water and heated toabout 67° C. Homogenization of this heated water solution in the 4 literglass flask reactor occurred utilizing an IKA Ultra Turrax T50homogenizer at about 4,000 revolutions per minute for about 30 minutes.The heated resin and initiator solution was then slowly poured into thewater solution over a period of about 10 minutes. The homogenizer speedwas increased to about 10,000 revolutions per minute and homogenizationcontinued for about 30 minutes. Upon completion of homogenization, theglass flask reactor and its contents were placed in a heating mantle andconnected to a distillation device. The mixture was stirred at about 400revolutions per minute and the temperature of the mixture was increasedto about 80° C. at about 1° C. per minute to distill off the ethylacetate from the mixture. Stirring continued at about 80° C. for about120 minutes followed by cooling at a rate of about 2° C. per minuteuntil the mixture was at room temperature.

The amount of crosslinked portion of the gel was measured by a toluenesolubility method, which was as follows. Approximately 40 mg of theabove gel emulsion, which was first dried, was weighed out into a glassscintillation vial to which about 20 ml of toluene was added. The samplewas shaken for about four hours on the low setting in a box shaker. Thedissolution of the sample in toluene was followed by a vacuumfiltration. The collecting membrane was dried under vacuum at about 65°C. for about four hours and weighed for % gel retained. About 6% of thegel produced above in Example 1 was determined to be crosslinked.

The product was screened through a 20 micron sieve and the pH wasadjusted to about 7 with the addition of about 1 N sodium hydroxide. Theresulting gel emulsion included about 32.72 percent by weight solids inwater, and had a volume average diameter of about 153 nanometers asmeasured with a HONEYWELL MICROTRAC® UPA150 particle size analyzer. Theonset glass transition temperature was about 61.9° C. as measured byDSC.

Example 2

This Example produced toner particles possessing a core/shellconfiguration, with about 28% by weight of a polyester gel from Example1 in the shell.

About 296.34 grams of the linear amorphous resin of formula I asdescribed in Comparative Example 1 above in an emulsion (about 17.02weight % resin) was added to a 2 liter beaker. About 62.99 grams of theunsaturated crystalline polyester resin, depicted as formula II inComparative Example 1 above, in an emulsion (about 17.53 weight %resin), and about 21.76 grams of a cyan pigment, Pigment Blue 15:3,(about 17 weight %) was added to the beaker. About 26.79 grams ofAl₂(SO₄)₃ (about 1 weight %) was added as flocculent underhomogenization by mixing the mixture at about 3000 to 4000 rpm.

The mixture was subsequently transferred to a 2 liter Buchi reactor, andheated to about 40° C. for aggregation and mixed at a speed of about 750rpm. The particle size was monitored with a Coulter Counter until thesize of the particles reached an average volume particle size of aboutof 7.42 μm with a Geometric Size Distribution (“GSD”) of about 1.23.

About 76.8 grams of the gel emulsion from Example 1 above was added as ashell, resulting in core-shell structured particles with an averageparticle size of about 8.96 microns, and a GSD of about 1.23.

Thereafter, the pH of the reaction slurry was increased to about 6.13using NaOH followed by addition of 0.45 pph EDTA (based on dry toner) tofreeze, that is stop, the toner growth. After stopping the toner growth,the reaction mixture was heated to about 90° C. and kept at thattemperature for about 0.5 hours for coalescence.

The resulting toner particles had a final particle size of about 8.24microns and a GSD of about 1.29 and a circularity of about 0.953.

The toner slurry was then cooled to room temperature, separated bysieving (utilizing a 25 μm sieve) and filtered, followed by washing andfreeze drying.

The rheology of the toners of this Example and the control toner ofComparative Example 1 above was determined by dynamic temperature stepmethod using a Dynamic Stress Rheometer SR 5000, made by MapleInstruments Inc., following the manufacturer's instructions. The resultsare set forth in FIG. 1. As can be seen in FIG. 1, the viscosity of thetoner of the present disclosure, possessing a polyester gel in theshell, was much higher than that of the toner of Comparative Example 1(which had a polyester, but not a polyester gel in the shell), at highertemperatures (from about 130° C. to about 160° C.). The increasedviscosity at this temperature range enabled reduction of peak glossduring fusing.

Fusing characteristics of the toners produced in Comparative Example 1and the Examples were also determined by crease area, minimum fixingtemperature, gloss, document offset, and vinyl offset testing.

Crease Area

The toner image displays mechanical properties such as crease, asdetermined by creasing a section of the substrate such as paper with atoned image thereon and quantifying the degree to which the toner in thecrease separates from the paper. A good crease resistance may beconsidered a value of less than 1 mm, where the average width of thecreased image is measured by printing an image on paper, followed by (a)folding inwards the printed area of the image, (b) passing over thefolded image a standard TEFLON coated copper roll weighing about 860grams, (c) unfolding the paper and wiping the loose ink from the creasedimaged surface with a cotton swab, and (d) measuring the average widthof the ink free creased area with an image analyzer. The crease valuecan also be reported in terms of area, especially when the image issufficiently hard to break unevenly on creasing; measured in terms ofarea, crease values of 100 millimeters correspond to about 1 mm inwidth. Further, the images exhibit fracture coefficients, for example ofgreater than unity. From the image analysis of the creased area, it ispossible to determine whether the image shows a small single crack lineor is more brittle and easily cracked. A single crack line in thecreased area provides a fracture coefficient of unity while a highlycracked crease exhibits a fracture coefficient of greater than unity.The greater the cracking, the greater the fracture coefficient. Tonersexhibiting acceptable mechanical properties, which are suitable foroffice documents, may be obtained by utilizing the aforementionedthermoplastic resins. However, there is also a need for digitalxerographic applications for flexible packaging on various substrates.For flexible packaging applications, the toner materials must meet verydemanding requirements such as being able to withstand the hightemperature conditions to which they are exposed in the packagingprocess and enabling hot pressure-resistance of the images. Otherapplications, such as books and manuals, require that the image does notdocument offset onto the adjacent image. These additional requirementsrequire alternate resin systems, for example that provide thermosetproperties such that a crosslinked resin results after fusing orpost-fusing on the toner image.

Minimum Fixing Temperature

The Minimum Fixing Temperature (MFT) measurement involves folding animage on paper fused at a specific temperature, and rolling a standardweight across the fold. The print can also be folded using acommercially available folder such as the Duplo D-590 paper folder. Thefolded image is then unfolded and analyzed under the microscope andassessed a numerical grade based on the amount of crease showing in thefold. This procedure is repeated at various temperatures until theminimum fusing temperature (showing very little crease) is obtained.

Gloss

Print gloss (Gardner gloss units or “ggu”) was measured using a 75° BYKGardner gloss meter for toner images that had been fused at a fuser rolltemperature range of about 120° C. to about 210° C. (sample gloss wasdependent on the toner, the toner mass per unit area, the papersubstrate, the fuser roll, and fuser roll temperature).

Document Offset

A standard document offset mapping procedure was performed as follows.Five centimeter (cm) by five cm test samples were cut from the printstaking care that when the sheets are placed face to face, they provideboth toner to toner and toner to paper contact. A sandwich of toner totoner and toner to paper was placed on a clean glass plate. A glassslide was placed on the top of the samples and then a weight comprisinga 2000 gram mass was placed on top of the glass slide. The glass platewas then inserted into an environmental chamber at a temperature of 60°C. where the relative humidity was kept constant at 50%. After 7 days,the samples were removed from the chamber and allowed to cool to roomtemperature before the weight was removed. The removed samples were thencarefully peeled apart. The peeled samples were mounted onto a samplesheet and then visually rated with a Document Offset Grade from 5.0 to1.0, wherein a lower grade indicates progressively more toner offset,ranging from none (5.0) to severe (1.0). Grade 5.0 indicates no toneroffset and no adhesion of one sheet to the other. Grade 4.5 indicatesnoticeable adhesion, but no toner offset. Grade 4 indicates that a verysmall amount of toner offsets to the other sheet. Grade 3 indicates thatless than ⅓ of the toner image offsets to the other sheet, while Grade1.0 indicates that more than ½ of the toner image offsets to the othersheet. In general, an evaluation of greater than or equal to 3.0 isconsidered the minimum acceptable offset, and an evaluation of greaterthan or equal to 4.0 is desirable.

Vinyl Offset

Vinyl offset was evaluated as follows. Toner images were covered with apiece of standard vinyl (32% dioctyl phthalate Plasticizer), placedbetween glass plates, loaded with a 250 gram weight, and placed in anenvironmental oven at a pressure of 10 g/cm², 50° C. and 50% relativehumidity (RH). After about 24 hours, the samples were removed from theoven and allowed to cool to room temperature. The vinyl and toner imagewere carefully peeled apart, and evaluated with reference to a vinyloffset evaluation rating procedure as described above for documentoffset wherein Grades 5.0 to 1.0 indicate progressively higher amountsof toner offset onto the vinyl, from none (5.0) to severe (1.0). Grade5.0 indicates no visible toner offset onto the vinyl and no disruptionof the image gloss. Grade 4.5 indicates no toner offset, but somedisruption of image gloss. An evaluation of greater than or equal to 4.0is considered an acceptable grade.

The results are summarized below in Table 1.

TABLE 1 Comparative Example Goal Example 1 2 DCX+ (90 gsm) paper ColdOffset 113 125 Hot Offset >210 >210 >210 T_(G40) ≦175° C. 142 N/A Gloss@ MFT 40 ggu 38.0 22.7 Gloss @ 185° C. ≧40 72.5 32.8 Peak Gloss ≧50 72.636.1 MFT_(CA=855) ≦169° C. 140 157 ΔMFT_(CA=85) Gloss 40 & CA = 85 −34−22 MFT/ΔMFT 142/.34 N/A FC_(CA=85) 4.34 4.55 Document Offset ≧1 1.00(15.1) 1.50 (4.7) (Toner-Toner) SIR (rmasLA) Document Offset ≧1 1.00(1.5)  1.25 (2.1) (Toner-Paper) SIR (% toner) DC EG (120 gsm) paperT_(G40) ≦175° C. 40 ggu 141 196 Gloss @ MFT 31.5 22.2 Gloss @ 185° C.≧40 80.2 33.8 Peak Gloss ≧50 94.1 48.9 MFT_(CA=85) ≦169° C. 137 162ΔMFT_(CA=85) −34 −20 MFT = Minimum fixing temperature (minimumtemperature at which acceptable adhesion of the toner to the supportmedium occurs) DCX = Uncoated Xerox paper DCEG = Coated Xerox paper gsm= grams per square meter CA = crease area T_(G40) = Fusing temperatureto reach 40 gloss unit

As can be seen from the above data in Table 1, the fusing resultsdemonstrated that image gloss was dramatically reduced with thepolyester gel in the toner shell, while still meeting crease MFTspecifications.

Scanning Electron Micrograph (SEM) images were obtained. The SEM imagesof the toner containing polyester gel in shell produced in this Example2, which was coalesced at 90° C., showed that the high viscosity shellprevented the crystalline polyester in the core from migrating to thesurface of the toner particles, even though the coalescence temperaturewas much higher than the melting point of crystalline polyester (about81° C.). In contrast, SEM images of the control toner of ComparativeExample 1, which had a polyester in its shell that was not cross-linked,demonstrated that coalescence had to be conducted at a temperature muchlower than the melting point of the crystalline polyester, to preventthe crystalline polyester from melting or coming to the toner surface.

Charging characteristics of the toner of the present disclosure with gelin the shell and the toner of Comparative Example 1 (no gel) were alsodetermined. The results are set forth in FIG. 2, which compares thecharging of the toner of the present disclosure with the toner ofComparative Example 1 (without the gel latex) in both A-zone and C-zone(in FIG. 2, Q/m is charge, AZ is A-zone, CZ is C-zone, 5M is 5 minutes,and 60M is 60 minutes). As can be seen in FIG. 2, the addition ofpolyester gel dramatically increased toner charging in A-zone and C-zonecompared with the toner of Comparative Example 1 (without gel), whichshows that adding a gel to the toner shell as disclosed herein was muchbetter at preventing the crystalline polyester in the core frommigrating to the toner particle surface, compared with the control shellthat was not a gel, regardless of the coalescence temperature.

It will be appreciated that various of the above-disclosed and otherfeatures and functions, or alternatives thereof, may be desirablycombined into many other different systems or applications. Also thatvarious presently unforeseen or unanticipated alternatives,modifications, variations or improvements therein may be subsequentlymade by those skilled in the art which are also intended to beencompassed by the following claims. Unless specifically recited in aclaim, steps or components of claims should not be implied or importedfrom the specification or any other claims as to any particular order,number, position, size, shape, angle, color, or material.

The invention claimed is:
 1. An emulsion aggregation toner comprising: acore particle comprising at least one amorphous polyester resin, atleast one crystalline polyster resin, and one or more optionalingredients selected from the group consisting of an optional colorant,an optional wax and combinations thereof; and a partially crosslinkedpolyester shell resin encapsulating aggregated core particles comprisingat least one amorphous resin selected from the group consisting ofpoly(propoxylated bisphenol co-fumarate), poly(ethoxylated bisphenolco-fumarate), poly(butyloxylated bisphenol co-funmarate),poly(co-propoxylated bisphenol co-ethoxylated bisphenol co-finnarate),poly(1,2-propylene fumarate), poly(propoxylated bisphenol co-maleate),poly(ethoxviated bisphenol co-maleate), poly(butyloxylated bisphenolco-maleate), poly(co-propoxylated bisphenol co-ethoxylated bisphenolco-maleate), poly(1,2-propylene maleate), poly(propoxylated bisphenolco-itaconate), poly(ethoxylated bisphenol co itaconate),poly(butyloxylated bisphenol co-itaconate), poly(co-propoxylatedbisphenol co-ethoxylated bisphenol co-itaconate), poly(1,2-propyleneitaconate), and combinations thereof, wherein about 5 wt % to about 35wt % of the amorphous resin is crosslinked, wherein the viscosity of theshell is greater than the viscosity of the core, and wherein the tonerexhibits a viscosity plateau at higher temperatures as compared to atoner without said polyester gel in the shell, and gloss of said toneris from about 20 ggu to about 100 ggu.
 2. The toner according to claim1, wherein the at least one amorphous resin of the core comprises apolyester selected from the group consisting of poly(propoxylatedbisphenol co-fumarate), poly(ethoxylated bisphenolco-fitmarate),poly(butyloxylated bisphenol co-fumarate), poly(co-propoxylatedbisphenol co-ethoxylated bisphenol co-fumarate), poly(1,2-propylenefumarate), poly(propoxylated bisphenol co-maleate), poly(ethoxylatedbisphenol co-maleate), poly(butyloxylated bisphenol co-maleate),poly(co-propoxylated bisphenol co-ethoxylated bisphenol co-maleate),poly(1,2-propylene maleate), poly(propoxylated bisphenol co-itaconate),poly(ethoxylated bisphenol co-itaconate), poly(butyloxylated bisphenolco-itaconate), poly(co-propoxylated bisphenol co-ethoxylated bisphenolco-itaconate), poly(1,2-propylene itaconate), and combinations thereof,and wherein the amorphous resin of the core and the amorphous resin ofthe shell may be the same or different.
 3. The toner according to claim1, wherein the at least one crystalline resin comprises a polyesterselected from the group consisting of polyethylene-adipate),poly(propylene-adipate), poly(butylene-adipate),poly(pentylene-adipate), poly(hexylene-adipate), poly(octylene-adipate),poly(pethylene-succinate), poly(propylene-succinate),poly(butylene-succinate), poly(pentylene-succinate),poly(hexylene-succinate), poly(octylene-succinate),poly(ethylene-sebacate), poly(propylene-sebacate),poly(butylene-sebacate), poly(pentylene-sebacate),poly(hexylene-sebacate), poly(octylene-sebacate), alkalicopoly(5-sulfoisophthaloyl)-copoly(ethylene-adipate), alkalicopoly(5-sulfoisophthaloyl)-copoly(propylene-adipate), alkalicopoly(5-sulfoisophthaloyl)-copoly(butylene-adipate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(pentylene-adipate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(hexylene-adipate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(octylene-adipate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(ethylene-adipate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(propylene-adipate), alkalicopoly(5-sulfo-isophthaloyl)copol(butylene-adipate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(pentylene-adipate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(hexylene-adipate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(octylene-adipate), alkalicopoly(5-sulfoisophthaloyl)-copoly(ethylene-succinate), alkalicopoly(5-sulfoisophthaloyl)-copoly(propylene-succinate), alkalicopoly(5-sulfoisophthaloyl)-copoly(butylenes-succinate), alkalicopoly(5-sulfoisophthaloyl)-copoly(pentylene-succinate), alkalicopoly(5-sulfoisophthaloyl)-copoly(hexylene-succinate), alkalicopoly(5-sulfoisophthaloyl)-copoly(octylene-succinate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(ethylene-sebacate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(propylene-sebacate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(butylene-sebacate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(pentylene-sebacate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(hexylene-sebacate alkalicopoly(5-sulfo-isophthaloyl)-copoly(octylene-sebarate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(ethylene-adipate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(propylene-adipate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(butylene-adipate), alkalicopoly(5-sulfo-isophthaloy)-copoly(pentylene-adipate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(hexylene-adipate), andpoly(octylene-adipate), wherein alkali comprises a metal selected fromthe group consisting of sodium, lithium and potassium.
 4. The toneraccording to claim 1, wherein the at least one amorphous resin of theshell comprises a poly(propoxylated bisphenol A co-fuimarate) resin ofthe formula:

wherein m may be from about 5 to about
 1000. 5. The toner according toclaim 1, wherein the core has a viscosity of from about 10 Poise toabout 1×10⁶ Poise, said shell has a viscosity of from about 1×10⁷ Poiseto about 5×10⁷ Poise or both.
 6. The toner according to claim 1, whereinthe at least one crystalline resin is of the formula:

wherein b is from 5 to 2000 and d is from 5 to
 2000. 7. The toneraccording to claim 1, wherein the colorant comprises dyes, pigments,combinations of dyes, combinations of pigments, arid combinations ofdyes and pigments, in an amount of from about 0.1 to about 35 percent byweight of the toner.
 8. The toner according to claim 1, wherein the waxis selected from the group consisting of polyolefins, carnauba wax, ricewax, candelilla wax, sumacs wax, jojoba oil, beeswax, niontan wax,ozokerite, ceresin, paraffin wax, microcrystalline wax, Fischer-Tropschwax, stearyl stearate, behenyl behenate, butyl stearate, propyl oleate,glyceride monostearate, glyceride distearate, pentaerythritol tetrabehenate, dietbyleneglycol monostearate, dipropyleneglycol distearate,diglyceryl distearate, triglyceryl tetrastearate, sorbitan monostearate,cholesteryl stearate, and combinations thereof, present in an amountfrom about 1 weight percent to about 25 weight percent of the toner. 9.The toner according to claim 1, wherein the toner is of a size of fromabout 3 to about 25 μm, possesses a circularity of from about 0.93 toabout 1 or possesses a parent toner charge per mass ratio of from about−3 μC/g to about −35 μC/g.
 10. The toner according to claim 1, whereinthe at last one amorphous resin in the core comprises a polyester gel.11. An emulsion aggregation toner comprising: a core particle comprisingat least one amorphous polyester resin, at least one crystallinepolyester resin, and one or more optional ingredients selected from thegroup consisting of an optional colorant, an optional wax, andcombinations thereof; and a partially crosslinked polyester shell resinencapsulating aggregated core particles comprising at least oneamorphous resin selected from the group consisting of poly(propoxylatedbisphenol co-fumarate), poly(ethoxylated bisphenol co-ftimarate),poly(butyloxylated bisphenol co-fumarate), poly(co-propoxylatedbisphenol co-ethoxylated bisphenol co-fumarate), poly(1,2-propylenefumarate), poly(propoxylated bisphenol co-maleate), poly(ethoxylatedbisphenol co-maleate), polytbutyloxylated bisphenol co-maleate),poly(co-propoxylated bisphenol co-ethoxylated bisphenol co-maleate),poly(1,2-propylene maleate), poly(propoxylated bisphenol co-itaconate),poly(ethoxylated bisphenol co-itaconate), poly(butyloxylated bisphenolco-itaconate), poly(co-propoxylated bisphenol co-ethoxylated bisphenolco-itaconate), poly(1,2-propylene itaconate), and combinations thereof,wherein about 5 wt % to about 35 wt % of the amorphous resin iscrosslinked and the shell resin prevents the crystalline resin in thecore particle from migrating to the toner particle surface, wherein thea viscosity of the shell is greater than the viscosity of the core, andwherein the toner exhibits a viscosity plateau at higher temperatures ascompared to a toner without said polyester gel in the shell, and glossof said toner is from about 20 ggu to about 100 ggu.
 12. The toneraccording to claim 11, wherein the at least one crystalline resincomprises a polyester selected from the group consisting ofpoly(ethylene-adipate, poly(propylene-adipate), poly(butylene-adipate),poly(pentylene-adipate), poly(hexylene-adipate), poly(octylene-adipate),poly(ethylele-succinate), poly(propylene-succinate),poly(butylene-succinate), poly(pentylene-snccinate),poly(hexylene-succinate), poly(octylene-succinate),poly(ethylene-sebacate), poly(propylene-sebacate),poly(butylene-sebacate), poly(pentylene-sebacate),poly(hexylene-sebacate), poly(octylene-sehacate), alkalicopoly(5-sulfoisophthaloyl)-copoly(ethylene-adipate), alkalicopoly(5-sulfoisophthaloyl)-copoly(propylene-adipate), alkalicopoly(5-sulfoisophthaloyl)-copoly(butylene-adipate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(pentylene-adipate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(hexylene-adipate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(octylene-adipate), alkalicopoly(5-sulfo-isophthaloyl-copoly(ethylene-adipate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(propylene-adipate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(butylene-adipate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(pentylene-adipate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(hexylene-adipate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(octylene-adipate), alkalicopoly(5-sulfoisophthaloyl)-copoly(ethylene-succinate), alkalicopoly(5-sulfoisophthaloyl)-copoly(propylene-succinate), alkalicopoly(5-sulfoisophthaloyl)-copoly(butylenes-succinate), alkalicopoly(5-sulfoisophthaloyl)-copoly(pentylene-succinate), alkalicopoly(5-sulfoisophthaloyl)-copoly(hexylene-succinate), alkalicopoly(5-sulfoisophthaloyl)-copoly(octylene-succinate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(ethylene-sebacate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(propylene-sebacate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(butylene-sebacate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(pentylene-sebacate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(hexylene-sebacate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(octylene-sehacate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(ethylene-adipate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(propylene-adipate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(butylene-adipate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(pentylene-adipate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(hexylene-adipate), andpoly(octylene-adipate), wherein alkali comprises a metal selected fromthe group consisting of sodium, lithium and potassium.
 13. The toneraccording to claim 11, wherein the colorant comprises dyes, pigments,combinations of dyes, combinations of pigments, and combinations of dyesand pigments, in an amount of from about 0.1 to about 35 percent byweight of the toner.
 14. The toner according to claim 11, wherein thewax is selected from the group consisting of polyolefins, carnauba wax,rice wax, candelilla wax, sumacs wax, jojoba oil, beeswax, montan wax,ozokerite, ceresin, paraffin wax, microcrystalline wax, Fischer-Tropschwax, stearyl stearate, behenyl behenate, butyl stearate, propyl oleate,glyceride monostearate, glyceride distearate, pentaerythritol tetrabehenate, diethyleneglycol monostearate, dipropyleneglycol distearate,diglyceryl distearate, triglyceryl tetrastearate, sorbitan monostearate,cholesterol stearate, and combinations thereof present in an amount fromabout 1 weight percent to about 25 weight percent of the toner.
 15. Thetoner according to claim 11, wherein the at least one amorphous resin ofthe shell comprises a poly(propoxylated bisphenol A co-fumarate) resinof the formula:

wherein m may be from about 5 to about
 1000. 16. The toner according toclaim 11, wherein the toner is of a size of from about 3 to about 25 μm, possesses a circularity of from about 0.93 to about 1 or possesses aparent toner charge per mass ratio of from about −3 μC/g to about −35μC/g.
 17. The toner according to claim 11, wherein the core has aviscosity of from about 20 Poise to about 1×10⁵ Poise, and wherein saidshell has a viscosity of from about 1×10⁷ Poise to about 5×10⁷ Poise.18. The toner according to claim 11, wherein the at least one amorphousresin of the core comprises a polyester selected from the groupconsisting of poly(propoxylated bisphenol co-fumarate), poly(ethoxylatedbisphenol co-fumarate.), poly(butyloxylated bisphenol co-furnarate),poly(co-propoxylated bisphenol co-ethoxylated bisphenol co-fumarate),poly(1,2-propylene fumarate), poly(propoxylated bisphenol co-maleate),poly(ethoxylated bisphenol co-maleate.), poly(butyloxylated bisphenolco-maleate), poly(co-propoxylated bisphenol co-ethoxylated bisphenolco-maleate), poly(1,2-propylene maleate), poly(propoxylated bisphenolco-itaconate), poly(ethoxylated bisphenol co-itaconate),poly(butyloxylated bisphenol co-itaconate), poly(co-propoxylatedbisphenol co-ethoxylated bisphenol co-itaconate), poly(1,2-propyleneitaconate), and combinations thereof, and wherein the amorphous resin ofthe core and the amorphous resin of the shell may be the same ordifferent.
 19. The toner according, to claim 11, wherein the at leastone crystalline resin is of the formula:

wherein b is from 5 to 2000 and d is from 5 to
 2000. 20. The toneraccording to claim 11, wherein the at last one amorphous resin in hecore comprises a polyester gel.